Surface coating for metal matrix composites

Abstract

A method of fabricating a metal matrix composite (MMC) tool includes coating at least a portion of an interior of a mold assembly with one or more layers of a material coating, where the mold assembly defines at least a portion of an infiltration chamber. Reinforcing materials are deposited into the infiltration chamber, and infiltrated with a binder material. One or more layers of the material coating may then be reacted with the binder material to form an outer shell on selected outer surfaces of the MMC tool.

What is claimed: 
     
       1. A method of fabricating a metal matrix composite (MMC) tool, comprising:
 coating at least a portion of an interior of a mold assembly with one or more layers of a material coating, the mold assembly defining at least a portion of an infiltration chamber; 
 depositing reinforcing materials into the infiltration chamber; 
 infiltrating the reinforcing materials with a binder material to form the MMC tool; and 
 reacting at least one of the one or more layers of the material coating with the binder material and thereby forming an outer shell on selected outer surfaces of the MMC tool during infiltration, wherein reacting at least one of the one or more layers of the material coating with the binder material comprises at least one of alloying with, undergoing a chemical reaction, diffusing into, and inter-diffusing with and thereby forming at least one of an alloy, an intermetallic, and a ceramic in-situ. 
 
     
     
       2. The method of  claim 1 , wherein the MMC tool is a tool selected from the group consisting of oilfield drill bits or cutting tools, non-retrievable drilling components, aluminum drill bit bodies associated with casing drilling of wellbores, drill-string stabilizers, a cone for roller-cone drill bits, a model for forging dies used to fabricate support arms for roller-cone drill bits, an arm for fixed reamers, an arm for expandable reamers, an internal component associated with expandable reamers, a sleeve attachable to an uphole end of a rotary drill bit, a rotary steering tool, a logging-while-drilling tool, a measurement-while-drilling tool, a side-wall coring tool, a fishing spear, a washover tool, a rotor, a stator and/or housing for downhole drilling motors, blades for downhole turbines, and any combination thereof. 
     
     
       3. The method of  claim 1 , wherein the one or more layers of the material coating further comprise reinforcing particles selected from the group consisting of a metal, a metal alloy, a superalloy, an intermetallic, a boride, a carbide, a nitride, an oxide, a ceramic, a diamond, and any combination thereof. 
     
     
       4. The method of  claim 1 , wherein the MMC tool is a drill bit and the mold assembly includes one or more of a mold, a gauge ring, and a funnel, and wherein coating at least the portion of the interior of the mold assembly comprises coating an inner wall of one or more of the mold and the gauge ring with the one or more layers of the material coating. 
     
     
       5. The method of  claim 1 , wherein the mold assembly includes at least one flow passageway, and wherein coating at least the portion of the interior of the mold assembly further comprises coating an exterior surface of the at least one flow passageway. 
     
     
       6. The method of  claim 1 , further comprising modifying outer surface material properties of the MMC tool with the one or more layers of the material coating, the outer surface material properties being selected from the group consisting of wear resistance, erosion resistance, abrasion resistance, stiffness, hardness, yield strength, ultimate tensile strength, fatigue life, lubricity, hydrophobicity, anti-balling characteristics, surface roughness, and surface energy. 
     
     
       7. The method of  claim 1 , wherein the one or more layers of the material coating comprise a material selected from the group consisting of a transition metal, a post-transition metal, a semi-metal, an alkaline-earth metal, a lanthanide, a non-metal, and any alloy thereof. 
     
     
       8. The method of  claim 1 , wherein the one or more layers of the material coating includes at least a first layer and a second layer, wherein the first layer and the second layer react together thereby forming at least one of an alloy, an intermetallic, and a ceramic in-situ. 
     
     
       9. The method of  claim 1 , wherein coating at least the portion of the interior of the mold assembly with the one or more layers of the material coating comprises depositing the one or more layers of the material coating with a process selected from the group consisting of physical vapor deposition, chemical vapor deposition, sputtering, pulsed laser deposition, chemical solution deposition, plasma enhanced chemical vapor deposition, cathodic arc deposition, electrohydrodynamic deposition, ion-assisted electron-beam deposition, electrolytic plating, electroless plating, thermal evaporation, spin coating, dipping the portion of the interior of the mold assembly in a molten metal bath, and forming and placing foils. 
     
     
       10. The method of  claim 1 , further comprising masking the interior of the mold assembly to selectively deposit the one or more layers of the material coating at desired locations on inner surfaces of the mold assembly. 
     
     
       11. The method of  claim 1 , further comprising varying a thickness of the one or more layers of the material coating at desired locations on inner surfaces of the mold assembly. 
     
     
       12. A drill bit, comprising:
 a bit body comprising a reinforced composite material made by infiltrating reinforcement materials with a binder material; 
 a plurality of cutting elements coupled to an exterior of the bit body; and 
 an outer shell disposed on selected outer surfaces of the bit body, the outer shell being made from one or more layers of a material coating deposited on at least a portion of an interior of a mold assembly used to fabricate the drill bit, wherein the outer shell results from at least one of the one or more layers of the material coating reacting with the binder material during infiltration, wherein reacting the at least one of the one or more layers of the material coating with the binder material comprises at least one of alloying with, undergoing a chemical reaction, diffusing into, and inter-diffusing with and thereby forming at least one of an alloy, an intermetallic, and a ceramic in-situ. 
 
     
     
       13. The drill bit of  claim 12 , wherein the one or more layers of the material coating further comprise reinforcing particles selected from the group consisting of a metal, a metal alloy, a superalloy, an intermetallic, a boride, a carbide, a nitride, an oxide, a ceramic, a diamond, and any combination thereof. 
     
     
       14. The drill bit of  claim 12 , wherein the mold assembly includes one or more of a mold, a gauge ring, and a funnel, and wherein an inner wall of one or more of the mold and the gauge ring is coated with the one or more layers of the material coating to produce the outer shell. 
     
     
       15. The drill bit of  claim 12 , wherein the mold assembly further includes at least one flow passageway, and wherein an exterior surface of at least one fluid cavity and the at least one flow passageway is coated with the one or more layers of the material coating to produce the outer shell. 
     
     
       16. The drill bit of  claim 12 , wherein the one or more layers of the material coating modify outer surface material properties of the drill bit selected from the group consisting of wear resistance, erosion resistance, abrasion resistance, stiffness, hardness, yield strength, ultimate tensile strength, fatigue life, lubricity, hydrophobicity, anti-balling characteristics, surface roughness, and surface energy. 
     
     
       17. The drill bit of  claim 12 , wherein the one or more layers of the material coating comprise a material selected from the group consisting of a transition metal, a post-transition metal, a semi-metal, an alkaline-earth metal, a lanthanide, a non-metal, and any alloy thereof. 
     
     
       18. The drill bit of  claim 12 , wherein the one or more layers of the material coating includes at least a first layer and a second layer, wherein the first layer and the second layer react together thereby forming at least one of an alloy, an intermetallic, and a ceramic in-situ. 
     
     
       19. The drill bit of  claim 12 , wherein the one or more layers of the material coating are deposited on the interior of the mold assembly using a process selected from the group consisting of physical vapor deposition, chemical vapor deposition, sputtering, pulsed laser deposition, chemical solution deposition, plasma enhanced chemical vapor deposition, cathodic arc deposition, electrohydrodynamic deposition, ion-assisted electron-beam deposition, electrolytic plating, electroless plating, thermal evaporation, spin coating, dipping the portion of the interior of the mold assembly in a molten metal bath, and fanning and placing foils. 
     
     
       20. The drill bit of  claim 12 , wherein the interior of the mold assembly is masked to selectively deposit the one or more layers of the material coating at desired locations on inner surfaces of the mold assembly. 
     
     
       21. A drilling assembly, comprising:
 a drill string extendable from a drilling platform and into a wellbore; 
 a drill bit attached to an end of the drill string; and 
 a pump fluidly connected to the drill string and configured to circulate a drilling fluid to the drill bit and through the wellbore, wherein the drill bit comprises: 
 a bit body comprising a reinforced composite material made by infiltrating reinforcement materials with a binder material; 
 a plurality of cutting elements coupled to an exterior of the bit body; and 
 an outer shell disposed on selected outer surfaces of the bit body, the outer shell being made from one or more layers of a material coating deposited on at least a portion of an interior of a mold assembly used to fabricate the drill bit, wherein the outer shell results from at least one of the one or more layers of the material coating reacting with the binder material during infiltration, wherein reacting the at least one of the one or more layers of the material coating with the binder material comprises at least one of alloying with, undergoing a chemical reaction, diffusing into, and inter-diffusing with and thereby forming at least one of an alloy, an intermetallic, and a ceramic in-situ. 
 
     
     
       22. The drilling assembly of  claim 21 , wherein the one or more layers of the material coating further comprise reinforcing particles selected from the group consisting of a metal, a metal alloy, a superalloy, an intermetallic, a boride, a carbide, a nitride, an oxide, a ceramic, a diamond, and any combination thereof. 
     
     
       23. The drilling assembly of  claim 21 , wherein the one or more layers of the material coating comprise a material selected from the group consisting of a transition metal, a post-transition metal, a semi-metal, an alkaline-earth metal, a lanthanide, a non-metal, and any alloy thereof.